What modality should I use for Zone 2?

Any low-impact, sustainable modality you will actually do. Bike, rower, SkiErg, incline treadmill walk, swim. Avoid high-impact running if you are also training heavy lower-body lifts in the same week. The single biggest predictor of success is which option you will repeat for six months, not which one is theoretically optimal.

I am over 40. Is it too late to build an engine?

It is the opposite. After 40, building an aerobic engine is the single most leveraged thing you can do for your healthspan. VO2 max is the strongest predictor of all-cause mortality after the age of 50, and most of it is trainable into your sixties and seventies. The right time to start was twenty years ago. The second right time is this week.

Why Strength Athletes Need an Engine

Why Strength Athletes Need an Engine from CrossFit BC. A Vancouver coach on why pure strength athletes need aerobic conditioning, how to build an engine without losing muscle, and what one weekly Zone 2 piece…

Written by:: CrossFit BC Coaching Team
Section:: Performance
Reading time:: 10 min
Topics:: strength, conditioning, hybrid athlete, aerobic base, programming, vancouver
Published:: Tuesday, May 19, 2026
Last updated:: Sunday, July 12, 2026

This article is part of the CrossFit BC journal, written by the coaching staff who run our classes in Olympic Village, Vancouver. We publish what we teach on the floor: training decisions, recovery, nutrition, and the honest tradeoffs behind them.

Common questions

Will conditioning actually steal my strength gains?

Not at the doses we recommend. Meta-analyses show interference effects are small to negligible when conditioning is under three sessions a week, under 30 to 45 minutes each, performed on a separate day from your priority strength session, and on a compatible modality like cycling, rowing, or SkiErg. The version of conditioning that kills gains is six days a week of high-impact running, which is not what we are...

What is Zone 2 and how do I know I am in it?

Zone 2 is the intensity where your aerobic system is doing most of the work and lactate is not yet accumulating. Practically, it is 60 to 70% of max heart rate, or the pace where you can still hold a full conversation through your nose. If you cannot nose-breathe, you are going too hard. If you can sing, you are going too easy.

How long until I notice a difference?

Resting heart rate usually drops within three to four weeks. Recovery between strength sets noticeably improves around week six. By month three, most athletes report better sleep, faster cold recovery, and either maintained or improved strength numbers. The longer-term effects, including VO2 max gains and the changes in cardiovascular risk, take six to twelve months of consistent work.